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Implemented more flexible blending modes for accelerated renderers

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This fixes bug 2594 - Propose new blend mode, SDL_BLENDMODE_BLEND_DSTA

	blendMode = SDL_ComposeCustomBlendMode(SDL_BLENDFACTOR_SRC_ALPHA,
	                                       SDL_BLENDFACTOR_ONE_MINUS_SRC_ALPHA,
	                                       SDL_BLENDOPERATION_ADD,
	                                       SDL_BLENDFACTOR_ZERO,
	                                       SDL_BLENDFACTOR_ONE,
	                                       SDL_BLENDOPERATION_ADD);

This fixes bug 2828 - Subtractive Blending

	blendMode = SDL_ComposeCustomBlendMode(SDL_BLENDFACTOR_SRC_ALPHA,
	                                       SDL_BLENDFACTOR_ONE,
	                                       SDL_BLENDOPERATION_SUBTRACT,
	                                       SDL_BLENDFACTOR_ZERO,
	                                       SDL_BLENDFACTOR_ONE,
	                                       SDL_BLENDOPERATION_SUBTRACT);


This goes partway to fixing bug 3684 - Add support for a pre-multiplied alpha blending mode

	blendMode = SDL_ComposeCustomBlendMode(SDL_BLENDFACTOR_ONE,
	                                       SDL_BLENDFACTOR_ONE_MINUS_SRC_ALPHA,
	                                       SDL_BLENDOPERATION_ADD,
	                                       SDL_BLENDFACTOR_ONE,
	                                       SDL_BLENDFACTOR_ONE_MINUS_SRC_ALPHA,
	                                       SDL_BLENDOPERATION_ADD);
This commit is contained in:
Sam Lantinga 2017-08-14 05:51:44 -07:00
parent f8e1874d01
commit c59d9923b3
16 changed files with 718 additions and 778 deletions
Download patch file Download diff file Expand all files Collapse all files

96
src/render/opengl/SDL_render_gl.c
View file

@ -55,6 +55,7 @@ static SDL_Renderer *GL_CreateRenderer(SDL_Window * window, Uint32 flags);
static void GL_WindowEvent(SDL_Renderer * renderer,
const SDL_WindowEvent *event);
static int GL_GetOutputSize(SDL_Renderer * renderer, int *w, int *h);
static SDL_bool GL_SupportsBlendMode(SDL_Renderer * renderer, SDL_BlendMode blendMode);
static int GL_CreateTexture(SDL_Renderer * renderer, SDL_Texture * texture);
static int GL_UpdateTexture(SDL_Renderer * renderer, SDL_Texture * texture,
const SDL_Rect * rect, const void *pixels,
@ -126,7 +127,7 @@ typedef struct
struct {
GL_Shader shader;
Uint32 color;
int blendMode;
SDL_BlendMode blendMode;
} current;
SDL_bool GL_EXT_framebuffer_object_supported;
@ -321,7 +322,7 @@ GL_ResetState(SDL_Renderer *renderer)
data->current.shader = SHADER_NONE;
data->current.color = 0xffffffff;
data->current.blendMode = -1;
data->current.blendMode = SDL_BLENDMODE_INVALID;
data->glDisable(GL_DEPTH_TEST);
data->glDisable(GL_CULL_FACE);
@ -428,6 +429,7 @@ GL_CreateRenderer(SDL_Window * window, Uint32 flags)
renderer->WindowEvent = GL_WindowEvent;
renderer->GetOutputSize = GL_GetOutputSize;
renderer->SupportsBlendMode = GL_SupportsBlendMode;
renderer->CreateTexture = GL_CreateTexture;
renderer->UpdateTexture = GL_UpdateTexture;
renderer->UpdateTextureYUV = GL_UpdateTextureYUV;
@ -595,6 +597,73 @@ GL_GetOutputSize(SDL_Renderer * renderer, int *w, int *h)
return 0;
}
static GLenum GetBlendFunc(SDL_BlendFactor factor)
{
switch (factor) {
case SDL_BLENDFACTOR_ZERO:
return GL_ZERO;
case SDL_BLENDFACTOR_ONE:
return GL_ONE;
case SDL_BLENDFACTOR_SRC_COLOR:
return GL_SRC_COLOR;
case SDL_BLENDFACTOR_ONE_MINUS_SRC_COLOR:
return GL_ONE_MINUS_SRC_COLOR;
case SDL_BLENDFACTOR_SRC_ALPHA:
return GL_SRC_ALPHA;
case SDL_BLENDFACTOR_ONE_MINUS_SRC_ALPHA:
return GL_ONE_MINUS_SRC_ALPHA;
case SDL_BLENDFACTOR_DST_COLOR:
return GL_DST_COLOR;
case SDL_BLENDFACTOR_ONE_MINUS_DST_COLOR:
return GL_ONE_MINUS_DST_COLOR;
case SDL_BLENDFACTOR_DST_ALPHA:
return GL_DST_ALPHA;
case SDL_BLENDFACTOR_ONE_MINUS_DST_ALPHA:
return GL_ONE_MINUS_DST_ALPHA;
default:
return GL_INVALID_ENUM;
}
}
static GLenum GetBlendEquation(SDL_BlendOperation operation)
{
switch (operation) {
case SDL_BLENDOPERATION_ADD:
return GL_FUNC_ADD;
case SDL_BLENDOPERATION_SUBTRACT:
return GL_FUNC_SUBTRACT;
case SDL_BLENDOPERATION_REV_SUBTRACT:
return GL_FUNC_REVERSE_SUBTRACT;
default:
return GL_INVALID_ENUM;
}
}
static SDL_bool
GL_SupportsBlendMode(SDL_Renderer * renderer, SDL_BlendMode blendMode)
{
GL_RenderData *data = (GL_RenderData *) renderer->driverdata;
SDL_BlendFactor srcColorFactor = SDL_GetBlendModeSrcColorFactor(blendMode);
SDL_BlendFactor srcAlphaFactor = SDL_GetBlendModeSrcAlphaFactor(blendMode);
SDL_BlendOperation colorOperation = SDL_GetBlendModeColorOperation(blendMode);
SDL_BlendFactor dstColorFactor = SDL_GetBlendModeDstColorFactor(blendMode);
SDL_BlendFactor dstAlphaFactor = SDL_GetBlendModeDstAlphaFactor(blendMode);
SDL_BlendOperation alphaOperation = SDL_GetBlendModeAlphaOperation(blendMode);
if (GetBlendFunc(srcColorFactor) == GL_INVALID_ENUM ||
GetBlendFunc(srcAlphaFactor) == GL_INVALID_ENUM ||
GetBlendEquation(colorOperation) == GL_INVALID_ENUM ||
GetBlendFunc(dstColorFactor) == GL_INVALID_ENUM ||
GetBlendFunc(dstAlphaFactor) == GL_INVALID_ENUM ||
GetBlendEquation(alphaOperation) == GL_INVALID_ENUM) {
return SDL_FALSE;
}
if (colorOperation != alphaOperation) {
return SDL_FALSE;
}
return SDL_TRUE;
}
SDL_FORCE_INLINE int
power_of_2(int input)
{
@ -1092,25 +1161,18 @@ GL_SetColor(GL_RenderData * data, Uint8 r, Uint8 g, Uint8 b, Uint8 a)
}
static void
GL_SetBlendMode(GL_RenderData * data, int blendMode)
GL_SetBlendMode(GL_RenderData * data, SDL_BlendMode blendMode)
{
if (blendMode != data->current.blendMode) {
switch (blendMode) {
case SDL_BLENDMODE_NONE:
if (blendMode == SDL_BLENDMODE_NONE) {
data->glDisable(GL_BLEND);
break;
case SDL_BLENDMODE_BLEND:
} else {
data->glEnable(GL_BLEND);
data->glBlendFuncSeparate(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA, GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
break;
case SDL_BLENDMODE_ADD:
data->glEnable(GL_BLEND);
data->glBlendFuncSeparate(GL_SRC_ALPHA, GL_ONE, GL_ZERO, GL_ONE);
break;
case SDL_BLENDMODE_MOD:
data->glEnable(GL_BLEND);
data->glBlendFuncSeparate(GL_ZERO, GL_SRC_COLOR, GL_ZERO, GL_ONE);
break;
data->glBlendFuncSeparate(GetBlendFunc(SDL_GetBlendModeSrcColorFactor(blendMode)),
GetBlendFunc(SDL_GetBlendModeDstColorFactor(blendMode)),
GetBlendFunc(SDL_GetBlendModeSrcAlphaFactor(blendMode)),
GetBlendFunc(SDL_GetBlendModeDstAlphaFactor(blendMode)));
data->glBlendEquation(GetBlendEquation(SDL_GetBlendModeColorOperation(blendMode)));
}
data->current.blendMode = blendMode;
}